Flexible substrates offer a number of advantages in making OLEDs, particularly in their ability to be fed through web handling equipment. A considerable effort has been devoted to making flexible substrates including metals, plastics, and glasses. However, each of these materials has so far failed to deliver the right combination of price/performance to meet commercial needs. Plastics fail to provide an adequate barrier to moisture and oxygen infiltration, leading to premature failure of the OLED device produced on the substrate. Metals and glasses provide adequate barrier properties but have their own limitations. For metals, the obvious problem is that the metal is not transparent and therefore requires a transparent barrier layer for the other surface. In addition, since metals are conductive, an insulating layer should be deposited on the metal so that the OLED can be fabricated on top of the barrier layer. This increases complexity and cost. A number of glass companies have demonstrated glasses thin enough to be rolled on cores of a foot or less and are therefore flexible enough for web-handling, as long as all the material limitations are obeyed. However, this glass is expensive to produce and handle, especially because of the very large weight of a roll of glass. When broken, these glasses produce extremely sharp shards, often compared to razor blades.
In spite of the advantages of a flexible substrate for manufacture, a flexible substrate often has inadequate durability or rigidity for the final application.